Authors:M. Yang, P. Chen, C. Tseng, S. Yeh, and P. Weng
Dinonylnaphthalene sulfonic acid (HD) has been used as a preconcentrating agent to enrich trace metal ions and to separate
the interfering elements such as Na, K, Cl and Br which normally exist in the natural aqueous systems. Experiments were performed
by extracting the ions in the aqueous medium with HD in n-hexane and subsequently back-extracted into a minimal volume of
acid solution. Factors influencing the extraction efficiency of the ions of interest were investigated. The preconcentration
technique developed in this study was applied to the determination of trace elements in biological and natural water samples
by neutron activation analysis.
A novel complex, [Pr(5-nip)(phen)(NO3)(DMF)]
(5-nip: 5-nitroisophthalic acid; phen: 1,10-phenanthroline, DMF: N,N-dimethylformamide),
was prepared and characterized by single crystal X-ray diffraction, elemental
analysis, IR spectrum and DTG-DSC techniques. The results show that the crystal
is monoclinic, space group P2(1)/n with a=11.0876(6) Å, b=12.8739(7)
Å, c=16.9994(8) Å; β=91.193(4)°, Z=4, Dc=1.822
Mg m–3, F(000)=1320.
Each Pr(III) ion is nine-coordinated by one chelating bidentate and two monodentate
bridging carboxylate groups, one chelating bidentate nitryl group, one DMF
molecule and one 1,10-phenanthroline molecule. The complex is constructed
with one-dimensional ribbons featuring dinuclear units and the one-dimensional
ribbons are further assembled into two-dimensional networks by strong π–π
stacking interactions. The complex has high stability up to 500°C. The
enthalpy change of formation of the compound in DMF was measured using an
RD496-III type microcalorimeter with the value of –9.214±0.173
CuO nanocrystals of different surface areas were prepared. All samples were characterized by X-ray diffraction, transition
electron microscope, thermogravimetry, Brunauer-Emmett-Teller technique, Fourier transform infrared spectroscopy, and Raman
spectroscopy. CuO nanocrystals showed a stable monoclinic structure. With increasing surface areas, the surface hydration
became significant, which is followed by shifts in infrared frequencies and Raman phonon modes. CuO nanocrystals were explored
as an additive to catalytic decomposition of ammonium perchlorate (AP). AP decomposition underwent a two-stage process. Addition
of CuO nanocrystals led to a downshift of high-temperature stage towards lower temperatures.
Authors:A. Ren, S. Yu, J. Han, P. Chang, C. Chen, J. Chen, and X. Wang
Humic substances have attracted great interest in the investigation of metal ion behavior in the environment because of their
special properties. Sorption and complexation of Pb2+ on MX-80 bentonite, LA bentonite, alumina and silica as a function of pH were studied in the presence and absence of fulvic
acid (FA). The experiments were carried out in 0.01M and 0.001M NaNO3 solutions under ambient conditions. The results indicate that sorption of Pb2+ on the solid samples is strongly dependent on pH and FA. The sorption of Pb2+ is not influenced drastically by ionic strength. The nature of minerals/oxides, nature of humic substances and the composition
of the solution are important factors in the behavior of metal ions in the environment. The results also indicate that FA
has a positive effect on Pb2+ sorption at low and a negative effect at high pH values, and the results are discussed in the comparative complexation between
FA-Pb2+ and Pb2+-minerals.
Authors:P. Chang, S. Yu, T. Chen, A. Ren, C. Chen, and X. Wang
Sorption of Th(IV) on Na-rectorite as a function of pH, ionic strength, soil humic acid (HA) and fulvic acid (FA) are studied
under ambient conditions by using a batch technique. The results indicate that the sorption of Th(IV) on Na-rectorite is not
only dependent on medium pH values, but also dependent on medium ionic strength and humic substances. Surface complexation
and cation competition exchange account for Th(IV) sorption on Na-rectorite. The sorption of Th(IV) on Na-rectorite decreases
with the increase on the concentration of NaNO3, Mg(NO3)2 and Ca(NO3)2, and increases with the increasing amount of HA/FA in the suspension/adsorbed on rectorite. Soil HA/FA enhances the sorption
of Th(IV) on rectorite at medium pH<4 drastically, but the presence of FA reduces the sorption of Th(IV) at medium pH>6, and
HA has no effect on Th(IV) sorption at medium pH>6. An interpretation for the results is attempted, considering the occurrence
of different sorption mechanisms.
Authors:D. Chen, J. Zhu, P. Yuan, S. Yang, T. Chen, and H. He
A series of anion-cation surfactants modified organoclays are prepared by incorporating both cationic surfactant, hexadecyltrimethylammonium
bromide (HDTMAB), and anionic surfactant, sodiumdodecyl sulfonate (SDS), to montmorillonite. The added amounts of surfactant
varied from 0.2 to 4.0 CEC of the used montmorillonite, similar to those reported in literature. A combination of elemental
analysis, X-ray diffraction and thermogravimetric analysis is used in the characterization of the resulting organoclays. The
experimental results show that anionic surfactants can not be intercalated into the montmorillonite whereas they can be loaded
onto cationic modified montmorillonite, resulting in a further increase of organic carbon content of the resulting organoclays.
This study demonstrates that SDS can be intercalated into montmorillonite interlayer space through the interaction with HDTMAB
rather than by ion exchange. The intercalation of SDS results in an increase of the basal spacing of the resulting organoclays
when comparing with HDTMAB modified montmorillonite and higher decomposition temperature of the intercalated surfactants when
comparing with them in bulk state. These new insights are of high importance in the application of organoclays in the fields
of remediation of polluted water and synthesis of clay based nanocomposites.
Authors:S. Chiu, P. Wang, P. Kao, J. Lin, D. Lin, and C. Chen
Hair samples from junior high school students in metropolitan areas of Taichung, Taiwan were tested for a total of 13 elements,
Al, Ag, Br, Cl, Cr, Fe, K, La, Mn, Na, Sc, Se, and Zn by instrumental neutron activation analysis (INAA) to establish seasonal
variations, gender and environmental exposures. The seasonal variations of hairs in 39 healthy students (18 males and 21 females;
age 13.3 ± 0.4 years; height, 158.0 ± 4.1 cm; weight, 53.4 ± 5.7 kg) were collected at 1.5-month intervals for 1 year starting
from late August, 2008. The concentrations of the above elements varied from 103 to 10−2 μg g−1 at different sampling times. A quantified index of agreement (AT) was introduced to help classify the elements. A smaller
AT indicated highly consistent quantities of specific metals in the hair while a larger AT indicated increased fluctuation,
i.e., less agreement. The different ATs in various hair samples were discussed. The concentrations of these elements are compared
with the data in the literature.
Authors:G. Zhong, S. Luan, P. Wang, Y. Guo, Y. Chen, and Y. Jia
thiourea complexes of antimony and bismuth triiodide were synthesized by a
direct reaction of antimony and bismuth triiodide with thiourea powder at
room temperature. The formula of the complex is MI3[SC(NH2)2]3(M=Sb, Bi). The crystal structure of the
complexes belongs to monoclinic system and the lattice parameters are a=1.4772 nm, b=1.6582
nm, c=2.0674 nm and β=90.81 for
and a=1.4009 nm, b=2.0170
nm, c=2.0397 nm and β=90.84 for
The infrared spectra reveal that the trivalent antimony or bismuth ion is
coordinated by the nitrogen atom, not the sulfur atom of the thiourea. Thermal
analysis shows that there are two times structure rearrangements or phase
transformation in the complexes from 100 to 170C.
Authors:S. Yang, X. Chen, P. Zhen, Q. Ye, X. Xie, and W. Liu
A simple and rapid HPLC method using a photodiode array (PDA) detector for the analysis of 3-hydroxycarboplatin and its related complex has been established for the first time. Separation of 3-hydroxycarboplatin and 3-hydroxy-1,1-cyclobutanedicarboxylic acid (3-HO-cbdca) was carried out on a Phenomenex ODS3 column using an aqueous solution containing 50 mM ammonium acetate and 5 mM sodium 1-octanesulfonate as the mobile phase. The flow rate was 0.8 mL min−1, the column temperature was 40°C, and the detection wavelength was 230 nm for 3-hydroxycarboplatin and 220 nm for 3-HO-cbdca. Different analytical performance parameters such as precision, accuracy, linearity, stability of the solution, specificity, limit of detection (LOD), limit of quantification (LOQ), and system suitability were determined using the Empower 2 software. The calibration curve of standard 3-hydroxycarboplatin showed good linearity (r = 0.9995) within the range 0.5–1.4 mg mL−1. The method was accurate and precise, with an average accuracy of 100.4% (RSD = 1.53%, n = 9), and the results of the system suitability test showed symmetrical peaks, good resolution (Rs), and repeatability. It can be applied to the quality control of 3-hydroxycarboplatin.
Authors:Q. Qian, W. Feng, J. Chen, P. Zhang, C. Chai, J. Pan, Y. Wu, S. Zheng, X. Liu, and Z. Chao
The iron contents in the hair and blood samples of 37 juvenile athletes who were supplemented with 0, 8 and 16 mg Fe/day, respectively, in the food of ferrous gluconatecontaining chocolate for 3 months were determined before and after the supplementation by INAA, SRXRF and blood analysis. The experimental results showed that after supplementation of the iron-fortified food, the normal ferritin level in the blood of the male athletes was attained and the iron content in the hair was increased with supplementation, but both are not in the positive proportion. Most of the female athletes had similar results. It is suggested that supplementation of 8 mg iron/day to juvenile athletes may be desirable.